Combined lost-motion and supplemental torque mechanism

ABSTRACT

A reflex photographic apparatus incorporates an operator reflex assembly which is moved during a photographic cycle to convert an optical path from a viewing-focusing mode configuration to an exposure mode configuration. Spring means are utilized to drive the assembly, via a four-bar linkage, from the viewing mode position to an exposure mode position quickly and while minimizing elastic rebound at the termination of the movement. A motor is utilized to return the assembly to the viewing mode position following a photographic exposure. A pair of override springs interconnect two of the elements of the four-bar linkage so as to provide a lost-motion connection between the operator reflex assembly and the motor means. Should the reflex assembly be restrained during its return movement, the lost-motion connection permits the motor to complete its cycle without overloading. Further, the override springs function to provide a supplemental torque to aid in moving the operator assembly from its viewing mode position to its exposure mode position.

United States Patent 1191 Blinow Sept. 25, 1973 COMBINED LOST-MOTION AND [73] Assignee: Polaroid Corporation, Cambridge,

' Mass.

22 Filed: Apr. 24, 1972 21 Appl. No.: 246,854

52 U.S. c1. 95/42, 185/37 [51] Int. Cl. G03b 19/12 [58] Field of Search 95/42, DIG. 2; 185/37, 40 R, 40 B; 267/85, 89, 151

[56] References Cited UNITED STATES PATENTS 3,673,935 7/1972 Coughlan 95/42 x 3,569,652 3/1971 Hauser 185/37 x Primary ExaminerSamuel S. Matthews Assistant Examiner-Michae| D. Harris AttorneyMichael Bard iiE] [57] ABSTRACT A reflex photographic apparatus incorporates an operator reflex assembly which is moved during a photographic cycle to convert an optical path from a viewing-focusing mode configuration to an exposure mode configuration. Spring means are utilized to drive the assembly, via a four-bar linkage, from the viewing mode position to an exposure mode position quickly and while minimizing elastic rebound at the termination of the movement. A motor is utilized to return the assembly to the viewing mode position following a photographic exposure. A pair of override springs interconnect two of the elements of the four-bar linkage so as to provide a lost-motion connection between the operator reflex assembly and the motor means. Should the reflex assembly be restrained during its return movement, the lost-motion connection permits the motor to complete its cycle without overloading. Further, the override springs function to provide a supplemental torque to aid in moving the operator assembly from its viewing mode position to its exposure mode position.

26 Claims, 8 Drawing Figures :iiiii illy slwmwniiiiimmw'x PATENTEB SEP 2 5 I973 saith 0P4 PATENTEB SEP25 I913 .H ggg SHEEI 2 [IF 4 PATENTED SEP2 51973 SHEET & 0F 4 BACKGROUND OF THE INVENTION The present invention relates generally to selfprocessing photographic cameras of the reflex type and, more particularly, to a reflex camera in which a specular surface is moved into the optical path of a taking lens when the camerais caused to assume an exposure mode configuration.

Certain photographic film materials are structured to directly record a positive image of any subject properly imaged and exposed thereon. Exemplary of such materials are the film units described in U. S. Pat. No. 3,415,644, entitled Novel Photographic Products and Processes and issued to E. H. Land on Dec. 10, 1968. Film units of this type are intended for use within the above-noted self-processing photographic cameras and incorporate all of the materials necessary to produce a positive photographic print immediately following their exposure. While being of a somewhat complex chemical makeup, the film units are physically structured to include a planar photosensitive element in laminar combination with a transparent image-receiving element. Specially packaged processing units are additionally included within the unit.

To image properly through a lens system upon the above-described film units, it is necessary that one or an odd number of specular surfaces be incorporated within the optical path extending from the camera lens to the exposure plane of the film unit. Although the film units are configured to provide a desirably large film format, certain improved photographic camera designs have taken advantage of the requisite specular surface to achieve somewhat compact overall camera structures.

Improved photographic cameras as above described are intended to perform in fully automated fashion while being structured so thinly and compactly as to be carried conveniently in the pocket of a garment. Typically, these improved cameras incorporate an optimum viewing and focusing system together with fully automatic exposure control and motorized automatic film processing. In effect, the fully automatic camera represents an instrumentality incorporating a complex, multi-step process control system.

For purposes providing optimum viewing performance as well as structural compactness, the auto mated camera preferably utilizes a form of single lens reflex viewing. As described and claimed in a copending application for Letters Patent by E. H. Land, entitled Reflex Camera, filed Apr. 14, 1970, Ser. .No. 28,567, and commonly assigned herewith, such reflex cameras normally assume a viewing-focusing mode configuration in which their exposure plane is isolated from scene illumination by a flat movable operator or mirror and viewing surface assembly. In a viewing configuration, the operator assembly serves a function of providing a surface upon which a scene, in reflex fashion, may be framed and focused in preparation for a photographic exposure. In accordance with a modified single lens optical operation, depression of a start button on the camera commences a multi-step control causing its components to assume an orientation securing an exposure chamber by closing its shutter through an electromagnetic drive system. When this chamber is secured, the camera is caused to commence an expo- 2. sure mode operation in which the earlier-described operator assembly is released for movement via a spring drive to uncover the exposure plane and provide a revised reflex optical path for subsequent exposure of the previously imaged scene.

As an exposure mode configuration is achieved, the automatic exposure control sub-system of the camera cycles through a regulated exposure interval following which the shutter again closes to secure the exposure chamber. The control system of the camera is then called upon to cock the operator assembly by driving it, via an electrical motor, into its viewing mode configuration. Prior to termination of the photographic cycle, an exposed photosensitive film unit is automatically removed from its position at the exposure plane and drawn through a motor-driven processing station. When the operator assembly has been cocked and returned to its orientation covering the exposure plane, the shutter is again opened to its maximum extent and the camera is ready for its next succeeding photographic cycle.

As mentioned previously, the operator assembly is cocked by driving it via an electrical motor into its viewing mode configuration. As a consequence, the operator assembly drive system will usually require an override form of drive linkage to assure proper seating at its cocked position. Such override feature is extremely difficult to incorporate within the confined housings of compact cameras without resorting to the use of relatively high-torque rate drive springs with their attendant undesirably high loads on the relatively small drive motor.

If the operator assembly encounters any interference during its movement toward its cocked or viewingfocusing mode position, the motor may be overloaded and damaged. Certainly, if the motor is overloaded enough, the power drain upon a power supply such as a battery may render it incapable of carrying out other functions during a given photographic cycle.

In dealing with some of the foregoing problems, certain prior art photographic cameras such as described in copending application, Ser. No. 103,219, filed Dec. 31, 1970, and commonly assigned herewith, incorporate a lost-motion connection within the drive system for moving the operator assembly between the exposure mode position and the viewing mode position. Movement of the operator assembly between these positions is accomplished through a system incorporating a four-bar linkage and a drive spring. The system is configured to minimize the time required for moving the operator assembly to its exposure mode position whilst also minimizing the elastic rebound of the operator assembly'when it reaches its exposure mode position.

Typically, a torsion spring is employed for moving the operator assembly to its exposure mode position. The torsion spring is prewound to minimize the operator assembly movement time and also reduce its elastic rebound upon reaching the exposure mode position. This is achieved by maximizing the residual torque of the drive spring at the exposure mode position of the operator assembly.

A prewound override torsion spring is provided within the drive system and is configured to serve a dual purpose. The override spring functions to insure that the operator assembly is fully seated in its viewing position by allowing the motor to remain energized for a select interval following the seating of the assembly. The override spring absorbs the resultant over-travel motion and biases the assembly into its viewing mode position. This permits more easily achieved manufacturing tolerances in the assembly return mechanism, since the components thereof do not have to cooperate to move the operator assembly the precise distance between the exposure mode position and the viewing mode position.

Additionally, the override spring serves to provide an override or lost-motion connection between the motor and the operator assembly. If the operator assembly encounters any interference during its motor-driven movement between the exposure and viewing mode positions, the override spring will allow the motor to finish its normal return cycle. The energy from the motor will be transferred to and stored in the override spring until such time as the interference is removed. When the interference is removed, the override spring returns the operator assembly to its viewing position and any overload or attendant damage to the motor will be alleviated.

The override torsion spring described hereinabove which is used in the device of application Ser. No. 103,219, aforesaid, is disposed concentrically within the low-rate torsional drive spring employed for moving the operator assembly to its erected position. Not only does the override torsion spring include undesired friction between its coils (due to its configuration) but the entire mechanism is somewhat complicated and difficult of assembly.

SUMMARY OF THE INVENTION The subject invention includes a camera of the single lens reflex type having a planar wall which fixedly secures a specular member interposed between a lens and a film plane. The invention further includes an operator assembly incorporating a reflex member having opposed reflecting surfaces. One of these reflecting surfaces functions to reflect the image of a subject to the film plane and the other of these reflecting surfaces functions as a reflective viewing screen.

The operator assembly is mounted for pivotal movement between a first position wherein the viewing screen is positioned at a focal plane overlying and proximate the film or exposure plane and a second position wherein the reflecting surface opposite the viewing surface is positioned overlying the .fixed specular surface so as to redirect an image toward the film or exposure plane. Thus, in the first position the reflex member functions as a component of the cameras viewing system, and in the second position it functions as part of the exposure system.

Spring means are employed for moving the operator assembly from its viewing mode position to its exposure mode position. The spring means are operatively connected to the operator assembly via a unique four-bar erecting linkage which functions to apply the proper driving torque to the operator assembly while minimizing any warpage of said operator assembly which might otherwise result from direct coupling with the spring drive means. Upon the completion of a photographic exposure, the operator assembly is returned to its viewing mode position via an electric motor which causes energy to be stored by said spring drive means while said operator assembly is returning to the viewing mode position.

A pair of preloaded tension springs are provided within the drive system connected between two of the links of said four-bar linkage so as to serve a three-fold purpose. The preloaded tension springs function as override springs to insure that the operator assembly is fully seated in its viewing-focusing position by allowing the motor to remain energized for a select interval following the seating of the assembly. The override springs absorb the resultant over-travel motion and bias the assembly into its viewing mode position. This permits reduced manufacturing tolerances, as aforesaid. Secondly, the manner of connection of the preloaded tension springs between said two links permits said links to move relative to one another so as to provide an override or lost-motion connection between the electric motor and the operator assembly. lf the operator assembly encounters any interference during its motor driven movement between the exposure and viewing mode positions, the override springs will allow the motor to finish its normal return cycle.

Thirdly, the preloaded tension springs are so disposed as to provide a supplemental torque to the ope rator assembly during its movement from the viewing mode position to the exposure mode position to insure the rapid travel thereof. The supplemental torque provided by the preloaded tension springs increases as the operator assembly approaches the exposure mode position and thus aids in reducing the elastic rebound amplitude of the operator assembly when it is suddenly halted at the exposure mode position. If such elastic rebound is not minimized, undesirable oscillation of the operator assembly can occur which would require theuser to delay the initiation of a photographic exposure for an undesirably long period following the attainment of the exposure mode position by the operator assembly. Further, a desired exposure may be ruined due to the movement of the reflex mirror (of the operator assembly) during the exposure;

The supplemental torque provided by said tension springs is accomplished by causing the force vector of said springs to move to a variable position eccentric of the pivotal axis between said two links from an initial override position whereat said vector intersects said pivotal axis.

In view of the foregoing, it is an object of the subject invention to provide a photographic camera of the single lens variety and incorporating a reflex member which functions as a component of both the viewing and exposure systems of said camera and wherein operation may be shifted from a viewing mode to an exposure mode and back to said viewing mode whilst minimizing the interruption of the users field of view and with a maximization of mechnical effficiency.

Another object of the present invention is to provide a driving mechanism for moving a reflex operator assembly from a first position to a second position and incorporating means for minimizing the effect on said mechanism of an obstruction in the path of said reflex operator assembly.

Still another object of the instant invention is to provide a single lens reflex camera incorporating means for moving a reflex member between a viewing mode position and an exposure mode position and incorporating means for providing a supplemental torque for driving said reflex member toward said exposure mode position as it approaches same.

A further object of the present invention is to provide a reflex photographic apparatus including an operator assembly movable between viewing and exposure mode positions and incorporating drive means for driving the operator assembly from the exposure mode position to the viewing mode position, said drive means incorporating override spring means for enabling said drive means to over-travel beyond a point necessary to move said operator assembly into its viewing mode position.

A still further object of the instant invention resides in the provision of a novel spring and linkage assembly for moving a reflex member between first and second positions while providing an increasing driving torque to said reflex member as it approaches said second position and accommodating an interruption in the movement of said reflex member from said second position to said first position.

DESCRIPTION OF THE DRAWINGS Other objects and many of the attendant advantages of the instant invention will be better appreciated and said invention will become clearly understood by reference to the following detailed description when considered in conjunction with the accompanying drawings illustrating one embodiment of the subject invention, wherein:

FIG. 1 provides a simplified side elevation of a single lens reflex photographic camera incorporating the subject invention;

FIG. 2 provides a simplified perspective of a portion of the photographic camera of FIG. 1 illustrating the novel operator assembly erecting mechanism;

FIG. 3 provides a simplified exploded perspective of the erecting mechanism of FIG. 2;

FIG. 4 provides a simplified functional representation of the operator assembly and erecting mechanism of FIG. ll whilst said operator assembly is in the override position;

FIG. 5 provides a simplified functional schematic of the components of FIG. 4 when the operator assembly has moved toward the exposure mode position an angular distance of FIG. 6 illustrates the relative positions of the components of FIG. 4 when the operator assembly has moved toward said exposure mode position an angular distance of FIG. 7 illustrates the relative positions of the components of FIG. 4 when said operator assembly has moved 30 from its initial viewing-focusing mode position toward said exposure mode position; and

FIG. 8 provides a simplified representation of the relative positions of the components illustrated in FIG. 4 whenthe operator assembly has reached the exposure mode position.

Referring to the drawings in more detail and, more particularly to FIG. 1, a photographic camera of the single lens reflex type is illustrated generally at 10 and is similar to the cameras which are the subject of U. S. Pat. application Ser. No. 28,567, filed Apr. 15, 1970, by Edwin H. Land, and commonly assigned herewith (Case 4081). The camera 10 isprovided with a forwardly disposed exposure control system housing 112 within which are mounted all of the components required to regulate light passing into the camera. These components include, but are not limited to, an objective lens assembly illustrated generally at 14, a shutter mechanism (not shown), and electronic control circuitry (not shown). A pair of film unit processing rolls l6 and w are provided within said camera I0 for properly processing an exposed film unit in a now wellknown manner.

The photographic camera It) is further provided with a bottom support portion 20 which serves as a receiving and retaining chamber for a film-laden cassette structure as at 22. The bottom support portion 20 extends to a rear wall portion 24 which extends upwardly to an elongated upper rear portion 26 which, in turn, extends to an elongated upper forward portion 28. The portions 20, 24, 26, and 20, and the housing 12 are pivotally interconnected as at 30, 32, 34, and 36 for movement between the extended position shown and a compact folded position (not shown). The portions 22, 26, and 28, and the housing 12 cooperate with each other in the extended position to define essentially four sides of a generally six-sided exposure chamber 38, the remaining two sides of the chamber 38 being closed by a flexible bellows 40 formed of any suitable opaque material.

The film-laden cassette structure 22, positioned overlying the bottom support portion 20 of the camera 110, is formed as a generally thin parallelepiped having a top open portion, the rectangular periphery of which is defined by an integrally formed ridge 42. The forwardmost facing side of the cassette structure 22 is formed incorporating an opening or slot 44 generally aligned with the line of tangency between the processing rolls l6 and 18.

The cassette structure 22 is removably insertable within a cassette receiving chamber at the bottom support portion 20 so as to consistently and accurately orient an exposure plane 46 established at the lowermost periphery of the film frame opening defined by the ridge 42. A detailed disclosure of mechanisms for supporting cassettes such as the cassette 22, as at the bottom support portion 20 within the camera 10, is contained in U. S. lat. application Ser. No. 29,753, filed Feb. 24, 1970, by Edwin H. Land and Alfred H. Bellows, and commonly assigned herewith.

Coincidentally situated at the exposure plane 46 is an uppermost one of a plurality of film units 48. As de scribed in more detail in U. S. Pat. No. 3,415,644, aforesaid, each of the plurality of film units 48 includes all of the materials necessary to produce a positive photographic print. Each of the plurality of film units 43 is physically structured to include a photosensitive element 50 positioned adjacent and in laminar relationship with an image-receiving element 22. The imagereceiving element 52 is located upwardly from the element 50 and is urged by spring means (not shown) into the exposure plane 46.

A rupturable container 54 of processing fluid is se-. cured to one end of the laminar assembly of the elements 50 and 52 and is located forwardly within the I cassette structure 22. The rupturable container 54 dispenses its processing fluid between the elements 50 and 52 when subject to appropriate compressive pressure by the processing rolls 16 and 18. Each of the plurality of film units 48 is adapted to be processed when advanced, rupturable container 54 foremost through the slot 44 and between the pressure applying processing rolls 16 and 18. The latter manipulation causes the rupturable container 54 to dispense its fluid contents between the elements 50 and 52 and to spread the fluid between and in contact with said elements 50 and 52.

The image-forming process is now well known in the art and involves a formation of transverse imageforming substances in the exposed photosensitive elementaccompanied by their diffusion in a manner forming visible, positive image.

In the illustrated one of the film units 48 and as described in said U. S. Pat.- No. 3,415,644, the processing fluid includes an opacifying agent which is spread as a layer between the photosensitive element 50 and the image-receiving element 52. The opacifying agent is opaque to actinic radiation and provides a background for the photosensitive transfer image evolved in the process.

The components of the camera 10 normally assume a configuration for operating in a focusing or viewing mode. During a photographic cycle, however, these components are reoriented to assume an exposure mode configuration. As best seen in FIG. 1, the components of the camera 10 are illustrated in solid line as they assume a focusing mode configuration. In this configuration, the objective lens assembly 14 focuses the light from a subject along an optical path which extends from the objective lens assembly 14 and across the exposure chamber 38 of the camera 10 until it impinges upon and is reflected from a stationary reflex mirror 56.

The stationary reflex mirror 56 is fixedly secured to the elongated upper rear portion 26 of the camera 10.

within the exposure chamber 38. The light reaching the stationary reflex mirror 56 from the objective lens assembly 14 is reflected from mirror 56 and the optical path courses to a viewing surface indicated generally at 58. The viewing surface 58 is reflective to light and reflects the light impinging thereon back to the upper portion of the stationary reflex mirror 56.

The camera 10 is provided with viewfinder apparatus indicated generally at 60 and which is secured to the elongated upper forward portion 28 of the camera 10 in a well-known manner. The viewfinder apparatus 60 is adapted for movement between folded and extended positions, and includes first and second optical elements (not shown), operatively associable for providing an image of a scene. The optical elements are mounted for movement relative to one another between operative viewing positions and inoperative storage positions. A collapsible shade 62 cooperates with the other components of the viewfinder apparatus 60 to reduce the admission of ambient light between said first and second optical elements when they are located in their respective operative viewing positions. For a more complete understanding and description of the viewfinder apparatus 60, reference may be had to copending application Ser. No. 141,554, filed May 10, 1971, and entitled Folding Camera (Case 4279).

A baffle plate 64 is secured within the camera 10 in a well-known manner adjacent the exposure chamber 38 and is provided with an aperture 66 which communicates between the exposure chamber 38 and the viewfinder apparatus 60, whereby any light reaching the viewfinder apparatus 60 from the exposure chamber 38 of the camera 10 must pass through said aperture 66.

The aperture 66 is so positioned that the means optical path courses from the upper portion of the stationary reflex mirror 56 through said aperture 66 into the viewfinder apparatus 60 which, in turn, forms a real, erect, unreverted image of a subject.

With the arrangement above described, the photographic camera 10 may be focused by adjusting the objective lens assembly 14 whilst simultaneously viewing the image on the viewing surface 58 from the viewfinder apparatus 60. With this focusing mode of opcration, the optical path may be considered to have a predetermined length and the objective lens assembly 14 may be considered to establish a focal plane which, when the camera is in a viewing-focusing mode, lies in coincidence with the viewing surface 58. For a more complete understanding of the optics of the viewing system herein described, reference may be had to copending application Ser. No. 98,356, filed Dec. 15, 1970, and entitled Reflex Camera and Viewing Device (Case 4092), which reveals a somewhat similar system which functions in an analogous manner.

The viewing surface 58 is mounted upon, or formed as an integral component of, an operator assembly shown generally at 68 and surface 58 is preferably somewhat smaller than, but with the same shape as, the film format at the exposure plane 46. If the viewing surface 58 has the same shape as the film format, it aids in framing the subjects; having the surface 54 slightly smaller than the film format, reduce the chance for accidentally cutting ofi a portion of the subject by a minor framing error.

Formed of a material opaque to light, to operator assembly 68 is generally planar configuration and is dimensioned to nest over the cassette structure 22. As a consequence of its configuration, the operator assembly 68 functions to light seal or cap the exposure plane 46 at which the uppermost one of the plurality of film units 48 is situated.

The operator assembly 68 is provided with a specular reflex mirror 70 on its surface opposite the viewing surface 58.

As best seen in FIG. 2, one end portion of the operator assembly 68 extends to a pair of spaced parallel hinge portions 72 and 74. A pair of spaced parallel support members 76 and 78 are rigidly secured to the bottom support portion-20 of the camera 10 in a wellknown manner and the hinge portions 72 and 74 are pivotally secured to said support members 76 and 78, respectively, as by pin means 80 and 82, respectively.

As best seen in FIGS. 2 and 3, the hinge portion 72 of the operator assembly 68 includes a centrally located slot 84 and is adapted to secure a pin 86, which extends transversely through the slot 84, in spaced parallel relation to the pin means 80. The hinge portion 72 forms one of the elements of a four-bar linkage assembly by which the operator assembly 68 may be driven between its viewing mode and exposure mode positions. A generally elbow-shape draw-down link 88 forms a second element of said four-bar linkage and is provided with a pair of coaxial, oppositely directed lugs Q0 and 92 which extend transversely thereof and are provided with neck portions 94 and 96, respectively. The link 88 extends to an end portion 98 which is partially received within the slot 84 and pivotally secured to the hinge portion 72 as by said pin 86. The drawdown link 88 extends to a bifurcated end portion I00 which defines an open-ended, U"-shape slot 102.

The third element of the four-bar linkage assembly is provided by a bifurcated crank assembly 104 which extends in one direction to a pair of spaced parallel supports 106 and 108 and in an opposite direction to an end portion 110. The spaced parallel supports 106 and portion 110 of the bifurcated crank assembly 104, ex-

tends in a direction parallel to the lug l 16,-and includes a neck portion 126.

The bifurcated crank assembly 104 is secuted to a shaft 128 so as to rotate therewith as by a pain 130, and

shaft 128 is rotatably secured to the bottom support portion 20 in a well-known manner. The bifurcated end portion 100 of the drag-down link 88 is slideably received within the slot 112 such that the U-shape slot 102 will slideably receive the pin 1 14. A pair of tension springs 132 and 134 maintain the elbow-shape dragdown link 88 and the bifurcated crank assembly 104 in movable engagement as will be explained hereinafter.

The tension spring l32is secured between the lug 90 of the drag-down link 88 and the lug 116 of the bifurcated crank assembly 104 in a well-known manner with one end portion of said tension spring 132 disposed within the neck portion 94 and the other end portion of tension spring 132 disposed within the neck portion 120. In like manner, the tension spring 134 is secured between the lug 92 and the lug 118 with one end portion of tension spring 134 disposed within the neck 96 and the opposite end portion of spring 134 disposed within neck 122. g

The fourth element of the four-bar linkage assembly is provided by the frame or bottom support portion 20 'of the photographic camera and said four-bar linkage assembly functions in a manner to be described in more detail infra.

As best seen in FIGS. 2 and 3, a crank 136 is fixedly secured to oneend portion of saidshaft 128 as by a pin 138. A sleeve 140 is positioned on said shaft 128 and is disposed betweena portion of said support portion 20 and the support 106 of said bifurcated crank assembly 104. A torsion spring 142 is wound about the sleeve 140 with one end portion of said spring 142 disposed about the neck portion 126 of the lug 124 and the oppositely directed end portion (not shown) of said spring 142 secured to said bottom support portion 20 in a well-known manner. As shown in FIG. 2, the torsion spring 142 is so wound as to unwind in a clockwise direction so as to effect clockwise movement of the crank assembly 104 with the shaft 128.

The crank 136 is provided with a lug 144 a predetermined radial distance from the axis of rotation of the shaft 128 and is further provided with an opening 146 in its end portion remote from said shaft 128. A support plate148 is secured in spaced parallel relation to a portion of the bottom support portion 20 as by a plurality of spacer bars, one of which is partially illustrated at 150. A preloadedtension spring 152 is connected at one end portion to the support plate 148 as at 154 and at its other end portion to the lug 144 in a well-known manner. A ram 156 forms a component of a kinematic linkage assembly (not shown) and extends to an end portion 158 having a lug 160 which is pivotally secured to the crank 136 via the opening 146. An electric motor 162 is connected via a spring clutch assembly 164 to a gear train 166 (only a portion of which is shown); said gear train 166 being operatively connected tosaid kinematic linkage assembly and, hence,

said ram 186. The motor 162. may typically be powered by a battery which may be supplied with the film-laden cassette structure 22 in a well-known manner and functions to drive the crank 136 via the ram 186 of the kinematic linkage assembly and the gear train 166 in a manner more fully described in copending application Ser.

- No. 134,733, filed Apr. 16, 1971, and entitled Reflex Camera (Case 4199) and commonly assigned herewith.

Referring again to FIG. 1, the opeator assembly 68 is shown in phantom both when in the exposure mode position at 168 and at a position 170 intermediate the exposure mode and viewing mode positions. With the operator assembly 68 in the position 168 and after completion of an exposure, electrical switches (not shown) within the photographic camera 10 are activated to energize the motor 162. The motor 162 will drive the gear train 166 via the spring clutch assembly 164 which, in turn, will drive the ram 156 via the kinematic linkage (not shown) toward the rear wall portion 24 of the camera 10 so as to rotate the crank 136 in a counterclockwise direction (looking into FIG. 2). Counterclockwise rotation of the crank 136 will be transmitted through the shaft 128 to the bifurcated crank assembly 104 which, in turn, will wind up the torsion spring 142 (which, it should be noted, is preloaded) by means of the connection between the lug 124 and one end portion of said torsion spring 142, as aforesaid. Such counterclockwise rotation of the crank 136 will also extend the preloaded tension spring 152 so as to increase the energy stored thereby.,Tlie tension springs 132 and 134 (both of which are preloaded) will cause the drag-down link 88 to move with the bifurcated crank assembly 104 and exert a force on the pin 86 causing the hinge portions 72 and 74 and, hence, the operator assembly 68 to rotate clockwise about the pin means and 82, toward the viewing mode position illustrated in solid lines in FIG. 1.

After the operator assembly 68 has assumed the viewing mode position of FIG. 1, capping the filmladen cassette structure 22, the motor 162 will continue running for a predetermined time interval to further store energy in the torsion spring 142 and the tension spring 152. It should be noted at this point that when the operator assembly 68 reaches the viewing mode position of FIG. 1, the pin 114 of the bifurcated crank assembly 104 will be in abutment with the closed end portion of the U-shape slot 102 of the drag-down link 88.

As the motor 142 continues to run for a predetermined assembly 104 will continue its counterclockwise rotation, causing the pin 114 to move along the U- shape slot 102 toward the open end thereof. Such motion of the bifurcated crank assembly 104 will cause the lugs 116 and 118 to move away from the lugs and 92, respectively, so as to stretch the tension springs 132 and 134 and increase the energy stored thereby. The increased loading of the tension springs 132 and 134 will exert a clockwise torque on the operator assembly 68 (about the pins 80 and 82) to insure that the operator assembly 68 is fully seated in the viewing mode position. The positions of the component portions of the four-bar linkage assembly when the operator assembly 68 is in the viewing mode position and the motor 162 has driven the pin 114 toward the open end of the slot 102, may be designated as the override position and is illustrated in FIGS. 2 and 4.

When the operator assembly 68 is in the viewing mode position and the components of the four-bar linkage assembly are in the override position (FIGS. 2 and 4) the longitudinal axis 172 of the pin 114 lies proximate the plane defined by the longitudinal axes 174 and 176 of the tension springs 132 and 134, respectively.

After the camera 10 is properly focused with respect to the desired subject, a photographic cycle is commenced by depression of a shutter release button (not shown) mounted upon the photographic camera 10. After the shutter release button is depressed, the tension spring 152 and the torsion spring 142 will exert a clockwise torque on the shaft 128, causing the bifurcated crank assembly 104 to rotate clockwise until the pin 114 has seated in the closed end portion of the U-shape slot 102. Further clockwise rotation of the crank 104 will cause the drag-down link 88 to exert a torque on the operator assembly 68 about the pins 80 and 82 via the pin 86. The driving torque exerted on the operator assembly 68 by the drag-down link 88 will be counterclockwise (looking in the direction of FIG. 1) so as to pivot the operator assembly 68 upward to the exposure mode position 168.

Referring to FIGS. 4 8 in more detail, it can be seen that when the operator assembly is raised from the override position of FIG. 4 (whereat the operator assembly is generally horizontal) to an angle of 10 with the horizontal, the longitudinal axes 174 and 176 of the tension springs 132 and 134, respectively, will no longer generally lie in a common plane with the longitudinal axis 172 of the pin 114. At this time, the tension springs 132 and 134 will, of course, exert a force on the drag-down link 88 (via the neck portions 94 and 96 of the lugs 90 and 92) along their longitudinal axes 172 and 174. It should also be noted that at this time the longitudinal axis 172 of the pin 114 is serving as the center-of pivot for the drag-down link 88 with respect to the crank 104. Inasmuch as the force exerted on the drag-down link 88 by the tension springs 132 and 134 no longer passes through the axis 172 or pivotal center of the drag-down link 88, there will be a net torque exerted on the drag-down link 88 about the pin 114 in a counterclockwise direction (looking into FIG. 5) which will tend to aid the tension spring 152 and the torsion spring 142 in effecting the erection of the operator assembly 68 to the exposure mode position 168 (illustrated in FIG. 1).

FIGS. 6, 7, and 8 illustrate the changes in position of the components of the four-bar linkage assembly as the operator assembly 68 moves successively to a position of 20 degrees with the horizontal (FIG. 6), 30 degrees with the horizontal (FIG. 7), and finally to the exposure mode position (FIG. 8).

It can be seen that when the operator assembly 68 has moved from the position of 10 degrees to the horizontal to with the horizontal, the perpendicular distance from the longitudinal axis 174 of the tension spring 132 to the longitudinal axis 172 of the pin 114 has increased. Similarly, it will be understood that the longitudinal axis 176 of the tension spring 134 (which lies in spaced parallel relation to the longitudinal axis 174) will be positioned at the same perpendicular distance from the axis 172 as the axis 174.

Further, it will be understood that the tension springs 132 and 134 are so designed and preloaded that the energy stored thereby and, hence, the tensile force ex- 12 erted between the lugs 90 and 92 and the lugs 116 and '1 18, respectively, will not vary appreciably as the operaxes 174 and 176 and the axis 172. Such increased counterclockwise torque exerted on the drag-down link 88 will exert a counterclockwise torque on the operator assembly 68 about the pins and 82 to effect continued upward movement of the operator assembly 68 toward the elongated upper rear portion 26 of the photographic camera 10. Similarly, the tension springs 132 and 134 will exert a progressively increasing counterclockwise torque tending to erect the operator assembly 68 to the exposure mode position as said operator assembly 68 successively moves from the position of FIG. 6 to that of FIG. 7 and finally to the fully erected position of FIG. 8. Thus, it can be seen that the tension springs 132 and 134 provide a torque which supplements that provided by the torsion spring 142 and the tension spring 152 in erecting the operator assembly 68 from the viewing mode position to the exposure mode position.

It should be noted that the erection process of the operator assembly 68 from the viewing mode position to the exposure mode position is a rapid one and that the energy for effecting such erection is supplied chiefly by the torsion spring 142 supplemented by the preloaded tension spring 152 in a manner more fully described in copending application Ser. No. 246,715, filed Apr. 24, 1972, and commonly assigned herewith. Because of the extremely rapid movement of the operator assembly 68 from the viewing mode position to the exposure mode position 168 (FIG. 1), there is some tendency for the operator assembly 68 to oscillate about the pin means 80 and 82 or bounce" when it initially reaches the position 168. The torsion spring 142 and the tension spring 152 are so designed as to minimize the effect of such bounce but, nevertheless, any bounce of the operator assembly 68 during a photographic exposure would result in altering the optical path and the exposure plane 46, thereby degrading the photographic image produced. As mentioned previously, the tension springs 132 and 134 provide a torque to the operator assembly 68 when it is in the exposure mode position 168 and this torque tends to maintain the position of the operator assembly 68 adjacent the elongated upper rear portion 26 of the camera 10. Such torque significantly aids the torsion spring 142 and the tension spring 152 in preventing undesired bounce" of the operator assembly 68 upon reaching the exposure mode position 168.

After an exposure has been completed, the electric motor 162 operates to drive the gear train 166 (via the spring clutch 164) and the gear train 166 will drive the kinematic linkage assembly and, hence, the ram 156 to effect counterclockwise rotation of the crank 136 and, hence, the bifurcated crank assembly 104. Counterclockwise rotation of the bifurcated crank 104 will carry with it the drag link 88 due to the tension springs 132 and 134 which interconnect said drag link 88 and the bifurcated crank assembly 104. Such counterclockwise movement of the bifurcated crank assembly 104 will cause the drag link to pivot the operator assembly 68 clockwise (looking into FIG. 1) about the pins 80 and 82 and toward the viewing mode position.

If, during the travel of the operator assembly 68 toward the viewing mode position, such movement were to become inadvertently obstructed, the bifurcated crank assembly 104 would continue to rotate in a counterclockwise direction such that the pin 114 would move toward the open end of the slot 102 in the bifurcated end portion 100 of the drag-down link 88. Such continued movement of the bifurcated crank assembly 104 while the movement of the operator assembly 68 is obstructed would cause the tension springs 132 and 134 to store the energy from the motor 162 and permit the gear train 166 and kinematic linkage assembly to complete its cycling in accordance. with the teachings of U. S. Pat. application Ser. No. 134,733 (Case 4199), aforesaid. Thus, the tension springs 132 and 134 function as override springs and provide a lost-motion connection between the electric motor 162 and the operator assembly 68.

It should be noted that when the cause of interference with the movement of the operator assembly 68 is removed, the tension springs 132 and 134 will cause the drag-down link to pivot the operator assembly 68 about the pins 80 and 82 toward the viewing mode position. Clearly, the lost-motion connection providedby the tension springs 132 and 134 prevents an obstruction as aforesaid from overloading the electric motor 162 and/or causing damage to the operator assembly 68 such as would occur without a provision for relative movement between the pin 114 and the drag-down link 88.

, When no obstruction is encountered by the operator assembly 68 as it is being driven toward the viewing mode position by the motor 162, said operator assembly 68 will continue its downwardmovement' towards the viewing mode position and the pin 114" of the bifrucated crank assembly 104 will be held'in engagement with the closed end of the U-shape slot 102 by the tension springs 132 and 134. After the operator as- 14 sembly 68 to the exposure mode position upon commencement of another photographic cycle.

it can readily be seen that many other variations and modifications of the present invention are possible in the light of the aforementioned teachings, and it will be apparent to those skilled in the art that various changes in form and in arrangement of components may be made to suit requirements without departing from the spirit and scope of the invention. It is, therefore, to be understood that within the scope of the appended claims the instant invention may be practised in a manner otherwise than is specifically described herein.

What is claimed is:

1. In combination with a reflex photographic camera of the type having operator means movable between a viewing position and an exposure position, apparatus sembly 68 has reached the viewing mode. position, the

motor 162 will continue to drive the geartrain 166 and the kinematic linkage assembly, for a predetermined interval, to effect counterclockwise rotation of the crank 136 and the bifurcated crank assembly 104. Such continued movement of said bifurcated crank assembly 104 will cause the pin 114 to move toward the open end of the U-shape slot 102 toward the override position illustrated in FIG. 4, whilst storing energy in the tension springs 132 and 134. The increased tension in the springs 132 and 134, due to the continued rotation of the bifurcated crank assembly 104 to the override position, will serve to insure that the operator assembly 68 is fully seated at the exposure plane 46 capping the cassette structure 22. As a result, the need for close manufacturing tolerances within the motor drive system for moving the operator assembly 68 from its expo-- sure mode position to its viewing mode position is alle-' viated. I

As more fully described in. copending application Ser. No. 246,715, the motor 162 not only drives the op erator assembly 68from the exposure mode position to the viewing mode position, but functions to wind up the torsion spring 142 and tension the spring 152 so as to store sufficient energy therein to erect the operator asincluding:

erecting means coupled with said operator means and actuable to move said operator means between said viewing and said exposure positions;

drive spring means for providing a rotational output of predetermined characteristic; actuator means driveably engageable with said erecting means and responsive and operatively connected to said drive spring means output for actuating said erecting means to move said operator means from one of said positions to the other of said positions; motor means having an output connected in driving relationship with said actuator means for effecting return movement of said operator means to said one of said positions by said erecting means; and

override means coupled between said actuator means and said erecting means for both providing kinetic energy to said operator means during its movement to said other of said positions and furnctioning as a lost-motion connection with said motor means when said operator means is restrained.

2. The invention pursuant to claim 1, wherein said erecting means is movable between an initial position and an override position while said operator means remains in said viewing position. v

3; The invention as recited in claim 2, wherein said operator means is articulately connected within said camera by hinge means and said erecting means includes a link arm pivotally connected to said hinge means and said actuating means include crank means operatively connected to said motor means and said drive spring means and in engagement with said link armso as to be both rotationally andtranslationally movable with respect thereto.

4. The invention as set forth in claim 3, wherein said override means includes spring means connected between said crank means and said link arm.

5. Apparatus for use with a reflex camera of the type having an operator assembly movable from a first position whereat it functions as a focusing screen to a second position whereat it functions as a reflex member for reflecting the image of a subject toward an exposure plane, said apparatus including:

motor means;

erecting means coupled to said motor means and said operator assembly for moving said operator assemblyfrom said first position to said second position and thence to said first position; and

override means connected to said erectingmeans for both supplying kinetic energy to said erecting means, urging same toward said second position and securing said operator assembly in said first position by supplying potential eneergy to said erecting means.

6. The invention according to claim 5, wherein said erecting means is movable between an initial position and an override position whilst said operator assembly remains in said first position. i

'7. The invention as set forth in claim 6, wherein said erecting means includes first and second members articulately and slideably interconnected and said override means is operative to slave said second member to said first member and maintain said interconnection.

8. The invention as related in claim 7, wherein said operator assembly is adapted to be articulately connected within said camera and said erecting mechanism includes a four-bar linkage assembly.

9. The invention as stated in claim 8, wherein said four-bar linkage assembly comprises a frame member; crank means rotatably connected to said frame member; link means articulately and slideably connected to said crank means; and hinge means fixedly secured to said operator assembly, articulately connected to said vframe member, and pivotally connected to said link means.

10. The invention pursuant to claim 9, wherein said override means includes spring means connected between said crank means and said link means and capable of exerting a force therebetween.

11. The invention as recited in claim 10, wherein said link means extends to define a slot and said crank means includes a pin slideably received within said slot transversely thereof.

12. The invention according to claim 11, wherein said pin defines a pivotal axis for said link means and the force vector of said spring means passes through said pivotal axis when said erecting means is in said override position.

13. The invention according to claim 11, wherein said spring means is preloaded so as to store a predetermined amount of energy.

14. The invention of claim 13, wherein the perpendicular distance between said pivotal axis and said force vector varies in a predetermined manner with the position of said operator assembly, whereby said spring means may exert a predetermined torque on said link means about said pivotal axis in a direction so as to assist in erecting said operator assembly to said second position.

15. The invention of claim 14, wherein said spring means includes at least one tension spring connected at one end portion to said link means, eccentric of the pivotal connection between said hinge means and said link means, and at its other end portion to said crank means eccentric of said pivotal axis provided by said pin.

16. A mechanism for use with a reflex photographic camera of the type having an operator assembly movable from a first position whereat it functions as a focusing screen to a second position whereat it fimctions as a reflex member for reflecting the image of a subject toward an exposure plane, said mechanism including:

a motor;

erecting linkage means coupled with said operator assembly and actuable to move said operator assembly between said first and second positions; spring-loaded drive means engageable with said erecting linkage means for actuating said erecting linkage means to move said operator assembly between said first and second positions; and

override means adapted to both provide a lostmotion connection between said motor and said operator assembly and to supply kinetic energy to said operator assembly to assist its movement to said second position.

17. The invention pursuant to claim 16, wherein said override means includes spring means interconnecting said erecting linkage means and said spring-loaded drive means.

18. The invention as stated in claim 17, wherein said erecting linkage means includes a crank and a link arm and said link arm is slaved to said crank by said spring means.

19. The invention as recited in claim 18, wherein said erecting linkage includes hinge means fixedly secured to said operator assembly and said link arm extends to one end portion articulately connected to said hinge means and to another end portion adapted to pivotally engage said crank.

20. The invention according to claim 19, wherein said spring means is connected between said crank and said link arm such that a force is exerted therebetween whose vector is a predetermined variable perpendicular distance from the pivotal axis of said link arm with respect to said crank.

21. The invention ofclaim 20, wherein said force vector is eccentric of the articulate connection between said hinge means and said link arm.

22. Kinematic apparatus for erecting an operator assembly, including:

frame means;

means for articulately connecting said operator assembly to said frame;

erecting linkage means coupled to said operator assembly and actuable to move said operator assembly between first and second angularly displaced positions;

spring-loaded drive means engageable with said erecting means for actuating said erecting linkage means to move said operator assembly between said first and second positions; and

override means adapted to both supply kinetic energy to said operator assembly during movement of same between said first and second positions and to permit predetermined movement of said erecting linkage means whilst said operator assembly remains in said first position.

23. The invention as recited in claim 22, further including crank means connected to said spring-loaded drive means and wherein said erecting linkage means includes a link arm pivotally connected to said operator assembly and pivotally engaging said crank means.

24. The invention pursuant to claim 23, wherein said override means includes spring means for maintaining engagement between said crank means and said link arm.

25. The invention according to claim 23, wherein said override spring means exerts a force between said crank means and said link arm, the vector of which is so disposed with respect to the common pivotal axis of said crank means and said link arm as to assist the movement of said operator assembly toward said second position.

26. The invention as stated in claim 25, wherein said vector passes through said common pivotal axis when said operator assembly is in said first position and said erecting means is in said override position. 

1. In combination with a reflex photographic camera of the type having operator means movable between a viewing position and an exposure position, apparatus including: erecting means coupled with said operator means and actuable to move said operator means between said viewing and said exposure positions; drive spring means for providing a rotational output of predetermined characteristic; actuator means driveably engageable with said erecting means and responsive and operatively connected to said drive spring means output for actuating said erecting means to move said operator means from one of said positions to the other of said positions; motor means having an output connected in driving relationship with said actuator means for effecting return movement of said operator means to said one of said positions by said erecting means; and override means coupled between said actuator means and said erecting means for both providing kinetic energy to said operator means during its movement to said other of said pOsitions and furnctioning as a lost-motion connection with said motor means when said operator means is restrained.
 2. The invention pursuant to claim 1, wherein said erecting means is movable between an initial position and an override position while said operator means remains in said viewing position.
 3. The invention as recited in claim 2, wherein said operator means is articulately connected within said camera by hinge means and said erecting means includes a link arm pivotally connected to said hinge means and said actuating means include crank means operatively connected to said motor means and said drive spring means and in engagement with said link arm so as to be both rotationally and translationally movable with respect thereto.
 4. The invention as set forth in claim 3, wherein said override means includes spring means connected between said crank means and said link arm.
 5. Apparatus for use with a reflex camera of the type having an operator assembly movable from a first position whereat it functions as a focusing screen to a second position whereat it functions as a reflex member for reflecting the image of a subject toward an exposure plane, said apparatus including: motor means; erecting means coupled to said motor means and said operator assembly for moving said operator assembly from said first position to said second position and thence to said first position; and override means connected to said erecting means for both supplying kinetic energy to said erecting means, urging same toward said second position and securing said operator assembly in said first position by supplying potential eneergy to said erecting means.
 6. The invention according to claim 5, wherein said erecting means is movable between an initial position and an override position whilst said operator assembly remains in said first position.
 7. The invention as set forth in claim 6, wherein said erecting means includes first and second members articulately and slideably interconnected and said override means is operative to slave said second member to said first member and maintain said interconnection.
 8. The invention as related in claim 7, wherein said operator assembly is adapted to be articulately connected within said camera and said erecting mechanism includes a four-bar linkage assembly.
 9. The invention as stated in claim 8, wherein said four-bar linkage assembly comprises a frame member; crank means rotatably connected to said frame member; link means articulately and slideably connected to said crank means; and hinge means fixedly secured to said operator assembly, articulately connected to said frame member, and pivotally connected to said link means.
 10. The invention pursuant to claim 9, wherein said override means includes spring means connected between said crank means and said link means and capable of exerting a force therebetween.
 11. The invention as recited in claim 10, wherein said link means extends to define a slot and said crank means includes a pin slideably received within said slot transversely thereof.
 12. The invention according to claim 11, wherein said pin defines a pivotal axis for said link means and the force vector of said spring means passes through said pivotal axis when said erecting means is in said override position.
 13. The invention according to claim 11, wherein said spring means is preloaded so as to store a predetermined amount of energy.
 14. The invention of claim 13, wherein the perpendicular distance between said pivotal axis and said force vector varies in a predetermined manner with the position of said operator assembly, whereby said spring means may exert a predetermined torque on said link means about said pivotal axis in a direction so as to assist in erecting said operator assembly to said second position.
 15. The invention of claim 14, wherein said spring means includes at least one tension spring connected at one end portion to said link means, eccentric of the pivotal connectIon between said hinge means and said link means, and at its other end portion to said crank means eccentric of said pivotal axis provided by said pin.
 16. A mechanism for use with a reflex photographic camera of the type having an operator assembly movable from a first position whereat it functions as a focusing screen to a second position whereat it functions as a reflex member for reflecting the image of a subject toward an exposure plane, said mechanism including: a motor; erecting linkage means coupled with said operator assembly and actuable to move said operator assembly between said first and second positions; spring-loaded drive means engageable with said erecting linkage means for actuating said erecting linkage means to move said operator assembly between said first and second positions; and override means adapted to both provide a lost-motion connection between said motor and said operator assembly and to supply kinetic energy to said operator assembly to assist its movement to said second position.
 17. The invention pursuant to claim 16, wherein said override means includes spring means interconnecting said erecting linkage means and said spring-loaded drive means.
 18. The invention as stated in claim 17, wherein said erecting linkage means includes a crank and a link arm and said link arm is slaved to said crank by said spring means.
 19. The invention as recited in claim 18, wherein said erecting linkage includes hinge means fixedly secured to said operator assembly and said link arm extends to one end portion articulately connected to said hinge means and to another end portion adapted to pivotally engage said crank.
 20. The invention according to claim 19, wherein said spring means is connected between said crank and said link arm such that a force is exerted therebetween whose vector is a predetermined variable perpendicular distance from the pivotal axis of said link arm with respect to said crank.
 21. The invention of claim 20, wherein said force vector is eccentric of the articulate connection between said hinge means and said link arm.
 22. Kinematic apparatus for erecting an operator assembly, including: frame means; means for articulately connecting said operator assembly to said frame; erecting linkage means coupled to said operator assembly and actuable to move said operator assembly between first and second angularly displaced positions; spring-loaded drive means engageable with said erecting means for actuating said erecting linkage means to move said operator assembly between said first and second positions; and override means adapted to both supply kinetic energy to said operator assembly during movement of same between said first and second positions and to permit predetermined movement of said erecting linkage means whilst said operator assembly remains in said first position.
 23. The invention as recited in claim 22, further including crank means connected to said spring-loaded drive means and wherein said erecting linkage means includes a link arm pivotally connected to said operator assembly and pivotally engaging said crank means.
 24. The invention pursuant to claim 23, wherein said override means includes spring means for maintaining engagement between said crank means and said link arm.
 25. The invention according to claim 23, wherein said override spring means exerts a force between said crank means and said link arm, the vector of which is so disposed with respect to the common pivotal axis of said crank means and said link arm as to assist the movement of said operator assembly toward said second position.
 26. The invention as stated in claim 25, wherein said vector passes through said common pivotal axis when said operator assembly is in said first position and said erecting means is in said override position. 